A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 55-year-old woman recently underwent kidney transplantation for end-stage renal disease. Her early postoperative period was uneventful, and her serum creatinine is lowered from 4.3 mg/dL (preoperative) to 2.5 mg/dL. She is immediately started on immunosuppressive therapy. On postoperative day 7, she presents to the emergency department (ED) because of nausea, fever, abdominal pain at the transplant site, malaise, and pedal edema. The vital signs include: pulse 106/min, blood pressure 167/96 mm Hg, respirations 26/min, and temperature 40.0°C (104.0°F). The surgical site shows no signs of infection. Her urine output is 250 mL over the past 24 hours. Laboratory studies show:
Hematocrit 33%
White blood cell (WBC) count 6700/mm3
Blood urea 44 mg/dL
Serum creatinine 3.3 mg/dL
Serum sodium 136 mEq/L
Serum potassium 5.6 mEq/L
An ultrasound of the abdomen shows collection of fluid around the transplanted kidney with moderate hydronephrosis. Which of the following initial actions is the most appropriate?
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A
Continue with an ultrasound-guided biopsy of the transplanted kidneyCorrect. POD 7 fever, oliguria, rising creatinine, and graft tenderness in a transplant patient mandate biopsy to distinguish acute rejection from ATN, calcineurin toxicity, or infection -- each of which has very different treatment.
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B
Consider hemodialysisIncorrect. Hemodialysis is supportive, not diagnostic; it does not address the underlying cause and would only be indicated for emergent dialysis criteria (refractory hyperkalemia, uremia, acidosis, volume overload).
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C
Re-operate and remove the failed kidney transplantIncorrect. Removal of the graft is a last-resort intervention for hyperacute rejection or graft necrosis; on POD 7 with no proven irreversible injury, biopsy first is mandatory.
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D
Supportive treatment with IV fluids, antibiotics, and antipyreticsIncorrect. Empirical antibiotics and fluids do not address the likely diagnosis (acute rejection) and delay the definitive workup; the surgical site is non-tender, making bacterial infection unlikely.
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E
Empiric pulse-dose IV methylprednisoloneIncorrect. Pulse steroids are the treatment for biopsy-proven acute rejection, not the initial step; treating presumptively without histology risks masking infection or calcineurin toxicity, which require entirely different management.
↑ Tap an answer to reveal the reasoning
Answer: A. This patient on postoperative day 7 from kidney transplant develops fever, oliguria, graft tenderness, rising creatinine (2.5 to 3.3 mg/dL), and hyperkalemia. The differential includes acute (T-cell mediated) rejection, antibody-mediated rejection, acute tubular necrosis, calcineurin-inhibitor nephrotoxicity, ureteral obstruction/urinoma, and pyelonephritis. The ultrasound shows hydronephrosis with a perinephric fluid collection -- features that mandate prompt evaluation.
An ultrasound-guided biopsy of the allograft is the definitive way to distinguish acute rejection (which requires intensified immunosuppression -- pulse steroids, anti-thymocyte globulin) from drug toxicity, infection, or ATN, which require very different management. Biopsy is the only test that establishes diagnosis with the specificity needed to guide therapy. The perinephric fluid can be sampled at the same time if needed.
Empirical antibiotics/fluids (D) miss the most likely diagnosis (rejection) and risk delay. Hemodialysis (B) is supportive at best and does not address the underlying problem; it would be needed only if the patient meets emergent dialysis criteria. Removal of the transplant (C) is a last resort reserved for refractory hyperacute or thrombotic graft loss, not a first step on POD 7. The initial action that drives all subsequent management is biopsy.
**Why each option:**
**A.** Correct. POD 7 fever, oliguria, rising creatinine, and graft tenderness in a transplant patient mandate biopsy to distinguish acute rejection from ATN, calcineurin toxicity, or infection -- each of which has very different treatment.
**B.** Hemodialysis is supportive, not diagnostic; it does not address the underlying cause and would only be indicated for emergent dialysis criteria (refractory hyperkalemia, uremia, acidosis, volume overload).
**C.** Removal of the graft is a last-resort intervention for hyperacute rejection or graft necrosis; on POD 7 with no proven irreversible injury, biopsy first is mandatory.
**D.** Empirical antibiotics and fluids do not address the likely diagnosis (acute rejection) and delay the definitive workup; the surgical site is non-tender, making bacterial infection unlikely.